In 2020 international shipping saw itself faced with new fuel regulations for cargo ships pertaining to low sulfur fuels (IMO2020). This reduced the emission of sulfur dioxide aerosols from these ships across the globe by about 80% practically overnight and resulting in perhaps the biggest unintentional geoengineering event since last century.
As detailed in a recent paper by [Tianle Yuan] et al. as published in Nature, by removing these aerosols from the Earth’s atmosphere, it also removed their cooling effect. Effectively this change seems to have both demonstrated the effect of solar engineering, as well as sped up the greenhouse effect through radiative forcing of around 0.2 Watt/m2 of the global ocean.
The inadvertent effect of the pollution by these cargo ships appears to have been what is called marine cloud brightening (MCB), with the increased reflectivity of said clouds diminishing rapidly as these pollution controls came into effect. This was studied by the researchers using a combination of satellite observations and a chemical transport model, with the North Atlantic, the Caribbeans and South China Sea as the busiest shipping channels primarily affected.
Although the lesson one could draw from this is that we should put more ships on the oceans burning high-sulfur fuels, perhaps the better lesson is that MCB is a viable method to counteract global warming, assuming we can find a method to achieve it that doesn’t also increase acid rain and similar negative effects from pollution.
Featured image: Time series of global temperature anomaly since 1980. (Credit: Tianle Yuan et al., Nature Communications Earth Environment, 2024)
The wording of the title is misleading. It should be “how fine particles in the atmosphere masked the real extend of global warming”. And this author definitely is often super biased.
It helps to be able to hold multiple facets of a more complex topic in one’s head at the same time. The diagram below at least leaves no doubt that the headline focuses on the observable effect. Everything that bumps the curve upwards is a worsening of the global warming issue.
I have yet to read the paper to know whether the potential impact was being considered when the decision was made to update fuel sulfur content regulations. Considering how surprising the experimental results are though, I’d guess the magnitude of emissions impact was not anticipated.
The article concludes saying “it’s a useful effect, but maybe we should look for something other than SO2 that contributes to acidification”, which I find to be a fair assessment. There are not many other types of global atmospheric alterations we can observe – volcanic eruptions being one of them, so anything we can glean from that is interesting.
global warming is about the temperature trend, and it is derived from many factors. that is, it is the derived property. if the temperature stops going up then global warming is counteracted, not masked. what is masked is presumably something like co2 rise.
I recently ran through the entire YouTube channel “Great moments in unintended consequences”.
I recommend this series, they’re all short, fast paced, and entertaining.
Several of them are climate related, and these plus my own memory of past climate remediation strategies (and the extra carbon each generated) has led me to be skeptical of ALL climate remediation strategies and policy changes.
Climate-related changes MUST start with a pilot program of limited scope, followed by measurements of a numerical value, and be defined using (ie – start with, before the program starts) clear goals and success metrics.
This thing about throwing everything against the wall is literally killing us. If you believe in climate change at all, you should be starting lots of little feasibility projects.
And not, for example, worldwide policy changes and hope.
Sounds like a great idea with the best of intentions! What could possibly go wrong?
Goodhart’s law codifies the issue: “When a measure becomes a target, it ceases to be a good measure.”
Goodhart’s law is an adage often stated as, “When a measure becomes a target, it ceases to be a good measure”. It is named after British economist Charles Goodhart, who is credited with expressing the core idea of the adage in a 1975 article on monetary policy in the United Kingdom:
“Any observed statistical regularity will tend to collapse once pressure is placed upon it for control purposes.”
It was used to criticize the British Thatcher government for trying to conduct monetary policy on the basis of targets for broad and narrow money, but the law reflects a much more general phenomenon.[1]
[1] Goodhart’s Law
https://en.wikipedia.org/wiki/Goodhart's_law
In this case, I don’t think the goal was to help with global warming but to instead reduce a pollutant that is bad for health but there was an unknown/underappreciated side effect of reducing global warming.
My positive take away is that it proves that human geoengineering can make a major impact on global climate change.
I wouldn’t call actions so far “throwing everything against the wall,” more of “just enough to be able to say we’re trying.”
I don’t think any pollution decreasing measures are a bad idea, even if they have extremely marginal (though very interesting) ancillary drawbacks like this one.
The obvious thing to do is to actually address carbon emissions, which we are nowhere near doing enough on.
I think pulling the sulphur out was meant to decrease the profoundly bad effect of “acid rain.”
The linked article is compelling but this kind of glossed over the bigger picture that shipping is responsible for an enormous amount of pollution- the contaminant was “good” only on the background of allllll the rest of the pollution being very, very “bad.”
Of course it’s impossible but if they were not gross polluters in existence at all the entire issue would be a moot point
I’m actually really excited about this – if the unintentional effect of dirty fuel blocking light can have such a big effect on ocean warming, then ocean “cloud brightening” is likely to be an effective and important method of offsetting warming in the future.
What, for instance, would be the effect of recruiting current shipping vessels to carry and run atomizing sprayers and leave intentional mist trails? Whether the shipper is actually complying and earning their subsidy/offset pay could be easily verified by satellite.
^ I wondered this too, it would be super simple for these ships to add a couple of big pumps and spray nozzles off the back and trail a huge cloud of mist for very little cost.
The sulphur was removed in the first place because spewing out what is essentially sulphuric acid clouds into the oceans and into the air is… you know, pretty not-great on the balance.
Yes, these would just be clouds of H2O. The lower sections would have some extra salt, since you’re misting salt water, but that would precipitate out with a quickness. IF the mist generated by ship-portable equipment stays in the air long enough and with enough density to nucleate decent clouds, it will replicate the reflective properties of ship trails without the annoying acid rain aspects.
Life has made me cynical enough that I think it will come down to a choice between acid rain and a warmer Atlantic ocean surface. The necessary equipment needs to be invented, and then someone needs to figure out a way to fund retrofitting existing ships and running this extra equipment that will take up cargo space and tonnage. I don’t even know which organization would have the authority to mandate such a large retrofit, let along manage inspections and maintenance.
Removing the sulphur didn’t make global warming worse, it simply stopped hiding how bad it actually really is.
We don’t need more band-aid measures, we need to stop the root causes.
The root causes? You mean modern civilization?
Exactly. An even more fundamental cause is overpopulation. Just like mouse plagues or locust plagues.
Microplastic will solve that problem.
Many country populations are decreasing far too rapidly. We need more people not less. Otherwise, there’ll be nobody reading Hackaday.
“Many country populations are decreasing far too rapidly. We need more people not less.”
How does one follow out of the other, unless you shoehorn the concept of infinite growth into a very finite reality? We built a system on top of the premise of ever-growing, because the world still had room and shareholders want to see the line go up. It’s obvious it was always going to be a temporary situation, no matter how much wishful thinking says otherwise. The atmosphere fills with pollutants, the ocean fills with plastics and orbit fills with junk, no matter how unendingly big they once seemed.
If anything, the population decline is the direct result of a system expecting growth, and the consequences when that expectation gets stretched beyond what reality can bear.
this is brilliant. my favorite comment of the day! So funny thanks for the chuckle.
Also known as a boom, where we really ought to want to find a sustainable way to avoid the coming bust. But instead we’d rather pretend things have always been like this and always will be no matter what we do.
Correct. One of the main reasons why Climate science deniers (or dismissive) tend to cite the 1970s as being a cooling period was because aerosols were doing an effective job of masking the global warming that was already happening: when Western nations started to reduce them (eg lower sulphur coal); temperatures started to increase. If we hadn’t had those aerosols in the first place, we would have seen the issue earlier.
Aerosols are an actual con as I see it, especially in the context of geoengineering, because you have to keep generating them (which costs energy) in order to offset radiative forcing from increased CO₂. But since the CO₂ and its forcing is persistent and growing, the aerosol offsets needed to correct the warming also needs to grow (because they don’t stay in the atmosphere for so long).
Which brings things back to the main point at the end of your comment: “we need to stop the root causes”.
Not sure I’d say aerosols are a con – if they can be generated easily & cheaply by renewable means (so effectively zero emissions) and their positive effect is greater than the effort what would be the problem?
As suggested above, adding a couple of pumps & misting sprayers to some of these cargo ships would be an insignificant cost and could have a significant impact, likewise you might imagine adding similar to offshore wind turbines since they are already nice tall structures with a power supply and sat in a supply of water.
See the novel Termination Shock by Neal Stephenson. It features a billionaire who attempts to reduce global warming by pumping large amounts of sulfur into the upper atmosphere.
Termination Shock: A Novel (Comment excerpted from the Amazon page for the book, ASIN 0063028050):
https://www.amazon.com/Termination-Shock-Novel-Neal-Stephenson/dp/0063028050/
“Ranging from the Texas heartland to the Dutch royal palace in the Hague, from the snow-capped peaks of the Himalayas to the sunbaked Chihuahuan Desert, Termination Shock brings together a disparate group of characters from different cultures and continents who grapple with the real-life repercussions of global warming. Ultimately, it asks the question: Might the cure be worse than the disease?”
So what’s the answer? Is the cure worse than the disease?
I came here for this comment. Thanks.
Is there some more benign substance which could be added to ship fuel which will increase cloud brightness?
Boy some folks just won’t ever learn about unintended second-order effects
In the end the gorillas will die during the winter, so there isn’t really even a problem.
Yes – billionaires.
“How Pollution Controls For Cargo Ships Made Global Warming Worse”
Wow, that’s a headline you will NEVER see on the ars technica site; Never Ever! Thank you Hackaday for being honest and bringing us all sides of the story.
Voting for those people isn’t going to fix the weather. I know this is tough to deal with, but both things can be true: pollution is very bad, and those people trying to sell you the solution are scammers and frauds who just want power. They’re completely malicious AND incompetent and need to be removed–gotten out of the way–for actual improvements to happen in our future.
I’m super confused. What happens then with ULSD currently in use in US and elsewhere for rolling stock?
Good news. Less pollution and fewer people dying from the weather (more people die from the cold),
Not to worry, ice age is scheduled within 5000 years.
you should read up on it, it is really stunning kind of thing to think about. the earth is extremely dynamic, changing dramatically from one century to the next. indeed, looking at the last few hundred thousand years of history, it seems very reasonable to predict an ice age soon.
however, looking at co2 concentration over that same history…it would go up and down…but the human-induced change over the past half century dwarfs the natural variation. relatively tiny changes in co2 over centuries were correlated with huge climactic changes. we are so far off of that chart now that it’s not really meaningful to predict a coming ice age. for better and worse, we are no longer on that path.
That is some unscientific and populistic reporting right there.
The extra pollution was like an always-on smoothing filter in a signal processor. Turn it off and you can see how noisy the signal actually was all along.
I did quit smoking in 2010. As a consequence I had to take vitamin D in the winter, just wasn’t outside in the parking lot as much as I used to be…